As an example of the image display device configured as above, Patent Document 1 discloses a device configured such that a monitor is caused to display a lattice-like, grid image providing a perspective in superposition over an actual image captured by a camera so as to allow monitoring of an area of viewing field that extends forwardly and to the left and right as being viewed from the driver.
This Patent Document 1 discloses an arrangement for setting the grid image at such a height not to be overlapped with the image of any important object which may be present on the road, such as a moving body, a traffic sign, etc. The document discloses also that upon detection of a moving object from within the actual image, the position, the moving speed, etc. of this moving body are acquired and information such as an arrow or the like is displayed on the monitor. The document further describes that a grid corresponding to the area where another vehicle is present is displayed with a more conspicuous color or when the outside of the vehicle is dark such as in the evening or at nighttime, white color is set while restraining the brightness of the grid.